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I think Ivo was talking about the item in natural light. Amber uranium glass does not tend to show the green glow on the curves so easily in daylight. Shape and glass thickness make little difference under a UV light. I am positive Ivo knows what a uranium glow looks like!!

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except the one on the left has a high Uranium content and shines like mad under UV

Hi Krsilber and CathyB, If you follow the URL link which Kev H has so kindly replaced from the old thread.Go down to Glasswipe comments and click the second photo you will see it "glowing" I took two photos one under UV blacklight conditions and one without.Hope you find this helpful.Kay

Cathy, the piece in your first photo is uranium, and that's an accurate photo of the glow? What color is it in daylight? It does seem strange that the whole thing doesn't glow.

I've heard that light emitted by uranium doesn't travel very far through glass (this needs to be confirmed before counting on its accuracy), which would account for the fact that it glows with an intensity not proportional to glass thickness.

I agree that it looks like Ivo's piece isn't stained (and that he'd know what uranium glass looks like). That's interesting that amber uranium pieces don't glow as strongly. Some glass components absorb certain wavelengths of light, iron among them. Iron in sufficient quantities is an amber colorant - I wonder if that is playing a role.

Another photo for comparison. All the pieces are colorless (the one at the top has an amber stain that glows bright orange). The jar on the right is Heisey; almost all clear Heisey glows bright yellowish green due to high manganese levels, and thicker glass is more intense than thinner. The comport on the bottom shows how cut edges of thin glass can glow brightly when the rest hardly glows at all, even when you're not looking through a lot more glass at those edges. Weird optical effect.

Cathy, the piece in your first photo is uranium, and that's an accurate photo of the glow? What color is it in daylight? It does seem strange that the whole thing doesn't glow.

Definitely uranium - it even glows under UV in full fluorescent light. It's very fine glass, with the slightest tinge of green in daylight. If you look carefully you'll see that the whole thing actually is glowing, just not nearly as brightly. It's the colour and intensity which gives it away as uranium - even in broad daylight, but with the UV on it, you can see the glow. But heck, just to prove it, I'll see whether I can rustle up a geiger counter.

Actually the effect is similar,but less pronounced, on all my uranium glass. Here's a tiny portion of my uranium glass taken under UV but in daylight conditions - note the colour is more intense in the areas of pattern.

Anyway, glasswipe's photo of her Breughel piece shows a glow worthy of a nuclear reactor. Ivo's is likely to be the same.

Sorry - I didn't mean to suggest that Ivo's piece (or yours) wasn't uranium glass, and you're right that Heisey's glow is a different color. I meant to contrast the effects, and also look at the optical properties of a cut edge. Sigh. I don't think I'm doing it very well or explaining myself very well, I should just butt out. I seem to be doing a poor job of posting lately.

Logged

Kristi

"The most beautiful thing we can experience is the mysterious. It is the source of all true art and all science."